This invention relates to polyisocyanate compositions containing polymers having a plurality of such moieties, as well as to polyurethanes which are prepared from such polyisocyanate compositions.
Polyurethanes, polyureas and similar polymers are commercially prepared by reacting an active hydrogen-containing composition with a polyisocyanate. By varying the characteristics of the polyisocyanate and the active hydrogen-containing composition, polymers having widely varying properties can be prepared. For example, by using relatively low equivalent weight, high functionality precursor materials, rigid polyurethanes are prepared. Conversely, flexible polyurethanes are prepared by using relatively high equivalent weight, low functionality precursor materials. By using or omitting blowing agents, cellular or non-cellular polyurethanes are prepared. Accordingly, polyurethanes can be prepared which are useful in a wide variety of applications.
It is often desirable to reinforce the polyurethane to give it better properties. For example, in preparing flexible polyurethane foams, it is known to employ dispersions of reinforcing polymer particles in a polyether polyol in order to obtain higher load-bearing and good cell opening. Similarly, the use of reinforcing fibers and fillers is common in non-cellular polyurethanes as well.
Due to the high cost of the reinforcing agents, and the processing difficulties imposed by their use, it is desirable to use the smallest amount thereof which provides adequate reinforcement. It is also desirable that the reinforcing agent be soluble or stably dispersable in the precursor materials used to make the polyurethane. Otherwise, the composition of the precursor material containing the reinforcing agent will vary over time, leading to compositional fluctuations during the processing of the polyurethane. Although these problems can often be resolved by continuously stirring the precursor material, this requires the use of special equipment which increases the overall cost of the polyurethane.
In addition, it is always desirable to further improve the properties of polyurethanes.
It would therefore be desirable to provide a polyurethane and/or polyurea polymer having improved physical properties. It would also be desirable to provide a precursor material containing a dissolved or stably dispersed reinforcing agent, which is useful in the preparation of polyurethanes.